Structure of poaching sturgeon species in the Irtysh River in 2013-2020 (according to ichthyologic examinations)

The study was carried out on the basis of the analysis of poaching sturgeon species in the lower reaches of the Irtysh River (the Tyumen region and Khanty-Mansi Autonomous Okrug), according to the results of forensic ichthyologic examinations over the period from 2013 to 2020. The size and weight ratio of Siberian sturgeon and sterlet in catches, the average weight of one fish species, the number of examinations performed, as well as the dynamics of these indicators for the considered time period were evaluated. As a result of the analysis performed, there has been seen an upward trend in the number of expert examinations (from 10 in 2013 to 25 in 2020). Among sturgeon species sterlet dominates in size, with the exception the period of 2017-2018. There has been stated the dynamics of increasing mass of Siberian sturgeon and, accordingly, a decrease for sterlet, with the average share of sturgeon to be less 50%. The average mass of a Siberian sturgeon species has increased from 0.8 to 1.2 kg, as well as a positive trend for the above period is noted when analyzing the total mass of sturgeon species during yearly examinations. Body mass of poached sterlet species hasn’t increased over the 8-year period, and its average value made 0.11–0.13 kg. Over the investigated period the number of forensic ichthyologic examinations has increased, the average mass growth dynamics in a Siberian sturgeon species has been stated, with predominating of immature species in both of sterlet and Siberian sturgeon catches.

Phytoplankton as an indicator of the current ecological status of the Ob River

The species composition, taxonomic structure, and the dominant complex of algae, and the distribution of phytoplankton abundance in the studied watercourse were identified based on data obtained for phytoplankton from the Ob River (from Tomsk to Salekhard) in summer 2019. Green algae (division Chlorophyta) make up the basis of the phytoplankton abundance in the river. The dominant complex is represented mainly by centric diatoms (genera Aulaсoseira, Cyclotella, Stephanodiscus) and non-heterocyst forms of cyanoprokaryotes (genus Aphanocapsa). The numbers and biomass of phytoplankton gradually decrease downstream of the Ob River; below the confluence of the Irtysh River, the edge effect occurs: increase in the diversity and density of organisms at the boundaries of ecosystems. Compared to the previous studies, the proportion of green and euglena algae, and cyanoprokaryotes in the taxonomic spectrum of phytoplankton increased, the composition of the dominant complex enriched, including due to non-heterocyst forms of cyanoprokaryotes, and the trophic status of the river increased to the category of eutrophic waters.

Migration of the Oirats in the first quarter of the 17th century on the eve of returning to Dzungaria

In 1541 the Oirats managed to form the Middle Confederation, which was led by the Khoshuts as the most powerful people. In the second half of the same XVI century the Oirats, suffering from attacks of their neighbors - the Turkic peoples from the west and south and the eastern Mongols from the east, began to move towards southern Siberia. Earlier they used to roam along the Black Irtysh river and north of the lake Zaysan, but now they began to move below the lake Yamysh. Opinions on the migration routes of the Oirats, existing in the literature, need clarification. The author offers his vision based on the archival materials and the Mongolian sources: the Hoyt Oirats, driven out of Kharakhoto by the Tumat Altan Khan, were the first to go towards the Altai Mountains. The next were the Torgut Oirats, who crossed the Altai, and then, together with the Derbets, they moved down the Irtysh river. The Elelets, the future Dzungars, left Western Mongolia for the Yenisei river sources. Already in the second decade of the 17th century the Oirats wandered along Om, Kamyshlov, Tobol and Ishim rivers, that is, they were roaming along the middle reaches of the Irtysh river. In 1623, at lake Yamysh, they defeated the troops of the Hotogoit Altyn Khan Sholoi Ubashi-Khuntaiji, but this victory did not exclude an internal struggle in the ruling house of the Khoshuts, which resulted in weakening of this people. Further civil strife forced the Torguts to move towards west, and in the early 1630s they reached the Volga river. Migrations over such long distances were possible only if there was an effective management apparatus, while maintaining traditions and identity.

Recommendations on the state of the sturgeon population of the irtysh river and its optimal extraction from the natural environment for reproduction

The results of studying the current state of the Siberian sturgeon population, clarifying the range of its distribution, the number and size-age groups in various sections of the Irtysh River are presented. Preliminary recommendations are given on the possibility of obtaining a small part of the population for the purpose of artificial reproduction. Ecological monitoring was carried out by the route-expedition method, by examining the Yertis River and the estuary areas of large flowing tributaries and reservoirs for the presence and distribution area of rare fish species. The work uses materials of research reports on the program 037 "State accounting and cadastre of fish resources" for 2004-14, data from the archives of Kazniirh LLP.When conducting research, we were guided by the provisions of Normative and methodological documentation. The research is funded by the Ministry of Ecology, Geology and Natural Resources of the Republic of Kazakhstan (Grant no. BR10264205)

MONITORING OF TRITIUM POLLUTION OF THE SHAGAN RIVER WATERS

The article presents the results of monitoring the waters of the Shagan river on the change in the specific activity of tritium for 2016–2020. The Shagan river is the longest surface watercourse on the territory of the Semipalatinsk Test Site, flowing along the eastern part of the Balapan site, where, together with the tributary, the Ashisu, flows into the “Atomic Lake”. Further, at a distance of 110 km downstream, the river forms a left-bank tributary of the Irtysh river. Previous studies have revealed and repeatedly confirmed the fact of radioactive contamination of the surface and ground waters of the Shagan river technogenic radionuclide 3H. It was revealed that the main source of pollution is groundwater entering the surface waters of the river. In this regard, in order to ensure long-term monitoring of 3H pollution of river waters, seasonal monitoring was carried out in three sections of the river located along its channel, starting from the outlet from the “Atomic Lake” heap and further downstream to the confluence with the Irtysh river.As a result of the observations, it was found that the specific activity of 3H in surface and ground waters, depending on the observation time, varies in a wide range of values. So, in the area of maximum pollution, the content of 3H changes from the minimum – 8 Bq/kg in the spring, to the maximum 370 000 Bq/kg in the summer-autumn period. At the exit points of the Shagan river outside the landfill, the concentration of 3H varies from 90 Bq/kg to 12 400 Bq/kg. In the area of the confluence of the Shagan river in Irtysh river content of 3H does not exceed 110 Bq/kg.

Identification and characterization of hybrids of Acipenser ruthenus and Acipenser baerii (Actinopterygii, Acipenseriformes) from the Irtysh River

Two sturgeon species, Acipenser ruthenus (Linnaeus, 1758) and Acipenser baerii (Brandt, 1869), inhabit the Irtysh basin. In 2018, we received some “atypical” specimens of sturgeon, which were similar to A. ruthenus but had a number of pronounced external differences. The hybrids A. ruthenus × A. baerii, named “oster”, can sometimes be caught in natural habitats in the Ob and the Yenisei rivers. Despite the development of methods for the genetic identification of sturgeons, the molecular genetic characteristics of the hybrids of A. baerii and A. ruthenus have not been carried out. The purpose of this study is to develop a complex of morphological and genetic characters to identify the hybrid of A. ruthenus and A. baerii from the Irtysh River. We used a complex of morphological and genetic methods to compare the putative hybrids with parental species The putative hybrids were similar to A. ruthenus in the number of dorsal scutes, the number of rays in the dorsal and anal fins, the structure of stamens on the first gill arch, and the presence of fringe on the tendrils. The hybrids were similar to A. baerii in size and weight values, the structure of dorsal scutes, the number of lateral and ventral scutes, and the number of gill rakers on the first gill arch. Genotyping of putative hybrids by using the Inter Simple Sequence Repeat (ISSR) markers revealed the presence of sites characteristic of both parental species. The fragment of the control region of mitochondrial DNA in the hybrids matched to that of A. baerii that allowed us to identify females of A. baerii as maternal individuals of the hybrids. Possible causes and factors promoting interspecific hybridization of A. ruthenus and A. baerii were studied. This is the first described fact of the appearance of sturgeon hybrids in the Ob-Irtysh basin. It is necessary to continue monitoring studies to identify the number of these hybrids in the ecological system of the Irtysh River. The data set of morphological characters and genetic methods can be used to identify the hybrids of A. ruthenus and A. baerii.

Modeling Snow Depth and Snow Water Equivalent Distribution and Variation Characteristics in the Irtysh River Basin, China

Accurate simulation of snow cover process is of great significance to the study of climate change and the water cycle. In our study, the China Meteorological Forcing Dataset (CMFD) and ERA-Interim were used as driving data to simulate the dynamic changes in snow depth and snow water equivalent (SWE) in the Irtysh River Basin from 2000 to 2018 using the Noah-MP land surface model, and the simulation results were compared with the gridded dataset of snow depth at Chinese meteorological stations (GDSD), the long-term series of daily snow depth dataset in China (LSD), and China’s daily snow depth and snow water equivalent products (CSS). Before the simulation, we compared the combinations of four parameterizations schemes of Noah-MP model at the Kuwei site. The results show that the rainfall and snowfall (SNF) scheme mainly affects the snow accumulation process, while the surface layer drag coefficient (SFC), snow/soil temperature time (STC), and snow surface albedo (ALB) schemes mainly affect the melting process. The effect of STC on the simulation results was much higher than the other three schemes; when STC uses a fully implicit scheme, the error of simulated snow depth and snow water equivalent is much greater than that of a semi-implicit scheme. At the basin scale, the accuracy of snow depth modeled by using CMFD and ERA-Interim is higher than LSD and CSS snow depth based on microwave remote sensing. In years with high snow cover, LSD and CSS snow depth data are seriously underestimated. According to the results of model simulation, it is concluded that the snow depth and snow water equivalent in the north of the basin are higher than those in the south. The average snow depth, snow water equivalent, snow days, and the start time of snow accumulation (STSA) in the basin did not change significantly during the study period, but the end time of snow melting was significantly advanced.

Species diversity of planktonic and zoobenthic communities of floodplain lakes in the middle reaches of the Irtysh river in the Omsk region

Based on hydrobiological studies conducted within the boundaries of the Omsk region, the species diversity of zooplankton and zoobenthic communities of floodplain lakes in the middle reaches of the Irtysh River is presented. The characteristics of zooplanktonic and zoobenthic invertebrates by qualitative and quantitative indicators are considered. The assessment of lakes by trophic and feeding capacity of reservoirs is given. The species diversity of the zooplankton and zoobenthic communities is shown. Zooplankton includes organisms of 20 genera from 11 families. The total number of species is 26, of which 12 are rotifers from two orders belonging to 5 families. Eleven species of branchiform crustaceans belonging to 10 genera from 4 families and three species of copepods belonging to 2 orders. It was found that the greatest species diversity was observed in the lake without the name of the Lubinsky district — 19, the smallest in such lakes as Staritsa, Peschanoe, and without the name of the Tavrichesky district — 12 taxa. The average abundance and biomass for the studied reservoirs was 75.9 thousand copies/m³ and 574.61 mg/m³, respectively. According to the average indicators of zooplankton biomass, floodplain lakes are characterized as ultra-oligotrophic reservoirs of the lowest productivity class. Zoobenthos community of floodplain lakes in the middle reaches of the river the Irtysh of the Omsk region, during the research period, is represented by 25 taxa belonging to three classes of organisms: insects( Insecta), leeches (Hirudinea) and small-scale worms (Oligochaeta). The larvae of chironomids (Sigopominae), mayflies (Ephemeroptera) and small-scale worms (Oligochaeta) formed the basis of the abundance and biomass. The average number of zoobenthos in floodplain lakes of the Omsk region during the study period was 465 specimens/m². The average biomass was 1.519 g/m². According to the average indicators of the biomass of the zoobenthos community, the floodplain lakes of the Omsk region belong to low-feed reservoirs, according to the trophic status — to the oligotrophic type of the low class.

State of aquatic bioresources in the area of production of non-metallic building materials on the Irtysh river

Sands and the sand-gravel mixes (SGM) from which more than a half of nonmetallic construction materials is manufactured in the Russian Federation serve as one of main types of the mineral raw materials used for production of the nonmetallic construction materials (NCM). Production of non-solid building materials (NSM) — sand, gravel, sand and gravel mixture — is necessary for the normal functioning of the construction industry: the larger the settlement, the greater the volume of production of NSM for construction enterprises. Many areas of the NSM are confined to the floodplain or channel of water bodies. Often, the interests of organizations engaged in the extraction of NSM near water bodies conflict with the interests of other water users, so the issue of regulating the production of NSM is very relevant. At the same time, environmental, hydrological aspects are the most important in the regulation, which are largely manifested through the deformation of the channel [1; 13–15]. In this article the assessment of the impact on water bioresources of the Irtysh River when developing fields on extraction of sand and sand-gravel mix on Oseredkovy, Pokrovsk and Molokan fields within the Omsk region is given. Comparative hydrobiological characteristic in the area of each deposit is given. Monitoring studies have shown that the main component of the damage in the extraction of non-solid building materials was fodder organisms. This work revealed changes in hydrobiological indicators in the number and biomass of fodder organisms depending on the location of deposits on the Irtysh River. The maximum amount of damage to water bioresources per 1000 m3 of mined soil is observed at the Molokanskoye deposit, the minimum loss of ichthyomass is noted at the Oseredkov deposit, which is located upstream of the river.